1. Field of the Invention
The present invention relates to a vehicular hood structure and a vehicle body front portion structure, and in particular to a vehicular hood structure and a vehicle body front portion structure that protects a collision body at the time of a collision in a vehicle such as an automobile.
2. Description of the Related Art
Conventionally, with respect to a vehicular hood structure that protects a collision body at the time of a collision in a vehicle such as an automobile, a configuration is known where one inner member formed by press molding is integrated with an outer member by hemming, and a lock reinforcement is attached between the outer member and the inner member at a hood lock striker support portion (e.g., see Japanese Patent Application Laid-Open Publication (JP-A) No. 11-321714). A configuration is also known where the thickness of an aluminium alloy serving as the outer member is 0.5 mm to 2.0 mm and a reinforcement member that lines the outer member is about 3 mm to 15 mm (e.g., see JP-A No. 2001-191962). A configuration including an annularly-formed outer frame and an inner skeletal member that bridges the outer frame along the vehicle body front-rear direction is also known (e.g., see JP-A No. 6-72355). A configuration where the lock reinforcement includes walls extending in the vehicle body front-rear direction at the left and right sides of a hood lock striker is also known (e.g., see JP-A No. 6-312670). A configuration where the inner member comprises an annular frame skeleton and an inner skeleton that forms a closed cross section by being coupled to the frame skeleton inward of the frame skeleton, and where the longitudinal walls of the cross section are substantially vertical surfaces, is also known (e.g., see JP-A No. 5-278637). A configuration where the side end portions of the hood curve back inward and end portions hang down is also known (e.g., see JP-A No. 2001-301541).
However, with respect to the technology of JP-A No. 11-321714, the production costs are high because the inner member is a large pressed part. Also, because the closed cross section, which is formed by the outer member and the inner member and extends in the vehicle body front-rear direction and the vehicle width direction, and the lock reinforcement are disposed, deformation of the hood for absorbing impact when a collision body collides with the hood is obstructed, a reaction force in the vehicle body front-rear direction is generated, and the impact absorbing efficiency is lowered.
With respect to the vehicular hood structure (FIGS. 4 and 8) of JP-A No. 11-321714, a configuration is known where, in an automobile hood (also called a bonnet) where an inner panel (also called an inner frame) is integrated with an outer panel, a reinforcement panel attached to the inner panel is folded in the shape of Mt. Fuji by a front slanted panel, a top panel and a rear slanted panel, with a slit being disposed in the top panel so that the top panel is divided into a front top panel and a rear top panel, and edge reinforcement members that reinforce the edges of the front top panel and the rear top panel are attached to the front top panel and the rear top panel, whereby, when a collision body hits the vicinity of the attachment portion of the striker from the outer panel side, the outer panel is deformed, the outer panel is received by the edge reinforcement members respectively disposed at the front top panel and the rear top panel, the energy of the collision body is initially absorbed, and then the front slanted panel and the rear slanted panel secondarily absorb the energy of the flexing obstacle.
However, in JP-A No. 11-321714, the reinforcement panel is disposed in the front portion region of the hood. As a result, when a collision body collides with the rear portion region of the hood, the reinforcement panel has no energy absorbing effect with respect to the collision body.
Moreover, in the vehicle body front portion structure (FIGS. 5, 6 and 7) of JP-A No. 11-321714, a configuration is known where, with respect to an automobile hood where the inner panel is integrated with the outer panel, the inner panel is one molded part that is press-molded, and an open portion is formed in the inner panel in order to reduce weight and improve hood rigidity.
However, in JP-A No. 11-321714, the closed cross-sectional structure is formed by adhering the edge portion of the open portion of the inner panel to the undersurface of the outer panel, and although hood rigidity is improved, the collision load on the collision body is not uniform, regardless of differences in the vehicle width direction of the collision positions, when a collision body collides with the front portion region of the hood.